This invention relates to an article storage and dispensing device for use in an automatic vending machine, and more particularly, to a device for detecting an empty or sold-out condition of the stored articles, which device is adapted for use in an automatic vending machine with a flapper-plate type and/or a helix type storage and dispensing mechanism.
Flapper-plate type and helix type article storage and dispensing mechanisms are well known as shown for example, in the U.S. Pat. of Kurosawa et al., No. 4,542,334 and the U.S. Pat. of Holstein et al., No. 3,335,907. In the constructions disclosed in these two prior art patents, means are provided for detecting an empty condition of the stored articles and to stop the vending machines and to indicate the empty condition to customers.
Referring to FIG. 1, there is shown a prior art sold-out detecting device designed for use in the flapper-plate type dispensing device. Within a cabinet 1 there is a vertically extending storage space 2 and a flapper-plate type dispensing device 3 disposed in the lower portion thereof. A control shaft 4, which controls the operation of dispensing device 3, is adapted to be rotated by a motor 5 arranged vertically within the storage space 2. The dispensing device 3 comprises at least one of flapper-plate (not shown) pivotally supported within the cabinet 1 and adapted to open and close a discharge opening, and a control plate 31 attached to the lower end of the control shaft 4 to open and close the flapper-plate as the control shaft 4 is rotated. The dispensing device 3 also includes an article holding element (not shown) to hold the next to last article in the stack of articles while the discharge opening is open and the lowermost article A1 is being dispensed.
As described in U.S. Pat. No. 4,542,834, in a device of this nature, the articles A which are stacked vertically on the flapper plate, are discharged one by one as the flapper-plate and control plate are operated. The means for detecting a sold-out condition comprises a microswitch 6 disposed in the cabinet 1 adjacent the lowermost article A1 and a pivoted plate 7 normally urged against the lowermost article A1 and having an arm adapted to engage the microswitch 6. If the articles are sold-out, the microswitch 6 is closed by the plate 7 to energize a sold-out light or indicator.
As articles are dispensed from the stack, the lowermost article drops onto the flapper-plate by sliding downwardly between the wall of the cabinet 1 and the plate 7. However, if the weight of the articles being dispensed is relatively light, the last article A3, without the benefit of the weight of any articles stacked on it, may not be sufficient to pivot the plate 7 out of the way or otherwise to move smoothly past the plate 7 and to come to rest on the flapperplate when the next to last article A2 is dispensed. Accordingly, the last article A3 in the stack can become hung-up and will not be dispensed, and thus, the sold-out indicator will not be actuated even though the cabinet will not dispense any further articles.